Simvastatin (C25H38O5) is butanoic acid, 2,2-dimethyl-,1,2,3,7,8,8a-hexahydro-3,7-dimethyl-8-[2-tetrahydro-4-hydroxy-6-oxo-2H-pyran-2-yl)-ethyl]-1-naphthalenyl ester, [1S-[1α,3α,7β,8β(2S*,4S*),-8αβ]] and belongs to a group of compounds called statins. Its structural formula is:

Simvastatin is a lipid lowering agent that is derived from a fermentation product of Aspergillus terreus. After oral ingestion, simvastatin is hydrolysed from an inactive lactone (as shown above) to the corresponding β-hydroxy-acid metabolite form. The β-hydroxyacid metabolite form is an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. This enzyme catalyzes the conversion of HMG-CoA to mevalonate, which is an early and rate-limiting step in the biosynthesis of cholesterol.
By inhibiting the endogenous production of cholesterol, simvastatin helps to reduce primary and secondary coronary diseases such as myocardial infarction and angina and cardiovascular events such as peripheral atrial disease and strokes.
Simvastatin is a white/off-white non-hygroscopic crystalline powder that is practically insoluble in water. The current brand leader, Zocor®, is sold in solid tablet form. The tablets are film coated and other components in the formulation include the antioxidants ascorbic acid and butylated hydroxyanisole, thus indicating the susceptibility of the product to oxidation. Presently, Zocor Tablets® are available in strengths of 10 mg, 20 mg, 40 mg and 80 mg, whilst the maximum daily dose of simvastatin for administering to adults is presently 80 mg/day. For administration to patients in the age range of 10 to 17 years old, the maximum daily dose is presently 40 mg/day.
Processes for making simvastatin have been described, for example, in U.S. Pat. Nos. 6,995,277; 6,984,399; 6,833,461; 6,825,362; 6,806,290; 6,797,831; 6,686,481; 6,649,775; 6,603,022; 6,576,775; 6,573,392; 6,506,929; 6,100,407; and 4,444,784. The aforementioned U.S. patents are hereby incorporated by reference.
Many patients, particularly the elderly, experience difficulty in swallowing tablets and/or capsules. This has resulted in the widespread practice of crushing tablets and opening capsules. Concerns have been raised over this practice, particularly the crushing of medicines that are for slow release or have enteric coatings, which may result in overdose and harm to the patient. Administering a medicine by crushing or opening may constitute the use of the medicine in unlicensed form and may render the person altering the medication liable for any harm caused.
There is an on-going need for medicines to be available in liquid form and which are suitable for oral administration whilst maintaining a suitable bioavailability of the drug and/or its active metabolite(s) after oral administration. As such, the present invention seeks to address these problems by providing a pharmaceutical composition comprising simvastatin which is in liquid form and suitable for oral administration. Preferably, the suspension is an aqueous suspension.